print backend: Remove an unneeded variable
print backend: Remove an unneeded variable

The G_DEFINE_TYPE macros automate the parent_class handling.

davidgumberg/gtk,grubersjoe/adwaita,alexlarsson/gtk,davidgumberg/gtk,jigpu/gtk,alexlarsson/gtk,alexlarsson/gtk,grubersjoe/adwaita,alexlarsson/gtk,grubersjoe/adwaita,grubersjoe/adwaita,jadahl/gtk,jigpu/gtk,alexlarsson/gtk,jadahl/gtk,davidgumberg/gtk,jadahl/gtk,alexlarsson/gtk,jadahl/gtk,alexlarsson/gtk,davidgumberg/gtk,jigpu/gtk,jadahl/gtk,davidgumberg/gtk,davidgumberg/gtk,jadahl/gtk,jigpu/gtk,jadahl/gtk,jigpu/gtk,jigpu/gtk,grubersjoe/adwaita,davidgumberg/gtk,grubersjoe/adwaita,davidgumberg/gtk,grubersjoe/adwaita,jadahl/gtk,grubersjoe/adwaita,jigpu/gtk,alexlarsson/gtk,jigpu/gtk